Chilblains

Chilblains (Pernio): A mild form of cold injury caused by a localized inflammatory reaction involving small blood vessels, nerves, and skin after exposure to cold and damp conditions.

Vascular Response: Exposure to cold causes constriction of small arteries and arterioles followed by a delayed and exaggerated re-warming (reactive hyperemia), which causes leakage from capillaries and subsequent inflammation.
Tissue Damage: This inflammatory response can lead to the formation of red to purple bumps, which are painful and/or itchy.

Demographics: More prevalent among young to middle-aged adults, predominantly females. Less common in children and the elderly.
Geographical Influence: Common in humid, temperate climates during colder seasons (late winter and early spring). Less frequent in extremely cold, dry climates due to better personal protection and adaptation.

Individual Susceptibility: Includes poor peripheral circulation, a history of frostbite, and hormonal changes.
Environmental: Living or working in damp, cold environments without adequate heating or clothing.
Medical Conditions:
- Connective Tissue Diseases: Especially systemic lupus erythematosus, which can manifest as chilblain lupus.
- Hematologic Disorders: Like chronic myelomonocytic leukemia.
- Vascular Disorders: Such as Raynaud’s phenomenon or acrocyanosis.
Lifestyle: Smoking, low body mass index, and poor nutritional status can predispose individuals to chilblains.
Occupational Hazards: Outdoor workers like fishermen and farmers are at increased risk.

Common Sites: Fingers, toes, ears, nose, and cheeks.
Symptoms: Initial redness and itching, progressing to painful inflammation and swelling. Lesions can become painful and may burn or itch severely.
Appearance: Lesions typically appear as small, red, swollen patches and can develop into blisters or ulcers in severe cases.

COVID-Toes: Reports during the pandemic indicated a surge in chilblain-like lesions in patients with mild or asymptomatic COVID-19, possibly due to immune reactions affecting the blood vessels.

Clinical Evaluation: Diagnosis is primarily based on the appearance of the skin and a history of exposure to cold.
Dermoscopy: Limited use but can help in excluding other differential diagnoses.
Biopsy: Not routinely performed but can confirm the diagnosis showing features of superficial and deep perivascular lymphocytic infiltration and edema.
Mayo Clinic Criteria: Includes persistent local redness and swelling, seasonal worsening, and improvement with warmth.

Prevention: Key to management, involving protection against cold, wearing warm clothes, and improving home heating.
Topical Treatments: Application of topical corticosteroids like betamethasone valerate to reduce inflammation and creams like nitroglycerin to improve circulation.
Systemic Treatments: Nifedipine to reduce the frequency and severity of episodes by dilating small blood vessels and improving blood flow; pentoxifylline for its rheologic benefits.
Lifestyle Modifications: Cessation of smoking and addressing nutritional deficiencies.

Complications: Severe chilblains can lead to skin breakdown, ulceration, and secondary infections.
Prognosis: Generally good as chilblains often resolve spontaneously within 1-3 weeks, though they can recur in colder seasons. Chronic or recurring chilblains may require ongoing management.

Frostbite: More severe cold injury that requires different management.
Chilblain Lupus Erythematosus: Part of the lupus spectrum and needs autoimmune management.
Vasculitis and Other Perniosis: Need consideration of systemic involvement.